电磁超声检测信号小波去噪研究
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摘要
针对电磁超声检测信号含有较多噪声的现象,使用小波分析方法进行了信号去噪。通过建立信号模型,从小波函数的选取、分解层数的选取、阈值函数和阈值的选取等几个方面进行了分析。采用强制去噪、默认阈值去噪、给定阈值去噪三种方法进行小波去噪仿真,比较得出给定阈值去噪方法效果最佳,在保留信号特征值的前提下达到了去除噪声的目的。
For the phenomenon of electromagnetic ultrasonic testing signal containing more noise, the wavelet analysis method is used for signal denoising. The signal model is established and the wavelet denoising is carried out from the several aspects of the selection of wavelet function, the selection of decomposition layers, the selection of threshold function and threshold. Using the compulsory denoising, default threshold denoising and given threshold denoising to complete the wavelet denoising simulation. By comparing these three denoising methods, it shows that the given threshold denoising method has the best result which can reserve the feature value of the signal effectively and achieve the purpose of removing the noise.
For the phenomenon of electromagnetic ultrasonic testing signal containing more noise, the wavelet analysis method is used for signal denoising. The signal model is established and the wavelet denoising is carried out from the several aspects of the selection of wavelet function, the selection of decomposition layers, the selection of threshold function and threshold. Using the compulsory denoising, default threshold denoising and given threshold denoising to complete the wavelet denoising simulation. By comparing these three denoising methods, it shows that the given threshold denoising method has the best result which can reserve the feature value of the signal effectively and achieve the purpose of removing the noise.
引文
[1] CHEN Q Y, WANG X M, LI M X. Sound field of an electromagnetic acoustic transducer[J]. Chinese Journal of Acoustics, 2011, 30(1): 44-54.
[2] 戴立新, 彭建平,杨凯,等. 电磁超声系统强噪声干扰抑制算法研究[J]. 铁道学报, 2011, 3(33): 35-39.
[3] 许霁, 邱玉,汪开灿,等. 钢轨踏面电磁超声检测信号处理方法[J]. 无损检测, 2012, 34(5): 34-36.
[4] X. JIAN, J. WEIGHT, K.T.V GRATTAN. A model for pulsed Rayleigh wave and optimal EMAT design[J]. Sensors and Actuators A Physical, 2006, 128(2): 296-304.
[5] 张广纯. 电磁声(EMA)检测技术的研究、开发与工程化[J]. 应用声学, 1994, 14(2): 1-6.
[6] 王帅, 陈鹏,刘美全,等. 基于小波包变换方法的超声回波信号去噪研究[J]. 国外电子测量技术, 2010, 29(8): 27-32.
[7] 赵晶. 管道腐蚀裂纹超声内检测信号处理研究[D]. 北京:北京化工大学, 2008.
[8] E SALAJEGHEH , A HEIDARI. Time history dynamic analysis of structures using filter banks and wavelet transforms[J]. Computers and Structures, 2005, 83(1): 53-68.
[9] R BUSSOW. An algorithm for the continuous morlet wavelet transform[J]. Mechanical Systems and Signal Processing, 2007, 21(8): 2970-2979.
[10] JH LEE ,DH Kim. Flaw detection in pipe welded zone by using wavelet transform and SH-EMAT[J]. Transactions of the Korean Society of Mechanical Engineers A, 2012, 36(12): 1511-1519.
[11] 张吉先, 钟秋海,戴亚平. 小波门限消噪法应用中分解层及阈值的确定[J]. 中国电机工程学报, 2004, 24(2): 118-122.
[12] 张德丰. MATLAB小波分析[M]. 北京: 机械工业出版社, 2009.
[2] 戴立新, 彭建平,杨凯,等. 电磁超声系统强噪声干扰抑制算法研究[J]. 铁道学报, 2011, 3(33): 35-39.
[3] 许霁, 邱玉,汪开灿,等. 钢轨踏面电磁超声检测信号处理方法[J]. 无损检测, 2012, 34(5): 34-36.
[4] X. JIAN, J. WEIGHT, K.T.V GRATTAN. A model for pulsed Rayleigh wave and optimal EMAT design[J]. Sensors and Actuators A Physical, 2006, 128(2): 296-304.
[5] 张广纯. 电磁声(EMA)检测技术的研究、开发与工程化[J]. 应用声学, 1994, 14(2): 1-6.
[6] 王帅, 陈鹏,刘美全,等. 基于小波包变换方法的超声回波信号去噪研究[J]. 国外电子测量技术, 2010, 29(8): 27-32.
[7] 赵晶. 管道腐蚀裂纹超声内检测信号处理研究[D]. 北京:北京化工大学, 2008.
[8] E SALAJEGHEH , A HEIDARI. Time history dynamic analysis of structures using filter banks and wavelet transforms[J]. Computers and Structures, 2005, 83(1): 53-68.
[9] R BUSSOW. An algorithm for the continuous morlet wavelet transform[J]. Mechanical Systems and Signal Processing, 2007, 21(8): 2970-2979.
[10] JH LEE ,DH Kim. Flaw detection in pipe welded zone by using wavelet transform and SH-EMAT[J]. Transactions of the Korean Society of Mechanical Engineers A, 2012, 36(12): 1511-1519.
[11] 张吉先, 钟秋海,戴亚平. 小波门限消噪法应用中分解层及阈值的确定[J]. 中国电机工程学报, 2004, 24(2): 118-122.
[12] 张德丰. MATLAB小波分析[M]. 北京: 机械工业出版社, 2009.